The objective of the research described in this proposal is to create antibody reagents that specifically recognize and neutralize the causative agent of severe acute respiratory syndrome, the SARS coronavirus (SARS-CoV). In addition, these antibodies could be used as diagnostic tools for the early detection of SARS in humans and animals. The Diversa Corporation recently received a NIAID grant RFA # which helped fund the creation of a novel fully human synthetic antibody library and the corresponding ultra-high throughput screening system. These technologies will be leveraged toward the isolation and optimization of human antibodies against SARS CoV to be used as effective control measures for the prevention of a possible epidemic or pandemic. Specific Aim 1: Isolate and characterize novel antibody leads that have diagnostic and/or therapeutic properties against the SARS coronavirus. Specific Aim 2: Optimize antibody leads against SARS for enhanced diagnostic and/or therapeutic properties. Specific Aim 3: Test efficacy of primary lead candidates for neutralization of SARS in novel in vitro infection model system.